#include<iostream>

#include<string>

class Test
{
    //初始化列表
    //const变量必须在初始化列表中初始化
    public:
    Test():a(0)
    {
    }
    void show()
    {
         //this指针：由编译器自己生成，指向当前对象
        std::cout <<this->a << std::endl;
    }
    private:
       const int a;
};
int main()
{
    Test t;
    t.show();
    return 0;
}